A circular coil ‘A’ has a radius R and the current flowing through it is I. Another circular coil ‘B’ has a radius 2R and if 2I is the current flowing through it, then the magnetic fields at the centre of the circular coil are in the ratio of (i.e. 
to
)
|
(a) 4 : 1 |
(b) 2 : 1 |
(c) 3 : 1 |
(d) 1 : 1 |
(d) 1 : 1
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
X-rays when incident on a meta
|
(a) Exert a force on it |
(b) Transfer energy to it |
|
(c) Transfer pressure to it |
(d) All of the above |
An electron microscope is superior to an optical microscope in
|
(a) Having better resolving power |
(b) Being easy to handle |
|
(c) Low cost |
(d) Quickness of observation |
An electric current passes through a long straight wire. At a distance 5 cm from the wire, The magnetic field is B. The field at 20 cm from the wire would be
|
(a) |
(b) |
(c) |
(d) |
The work function of aluminium is 4.2 eV. If two photons, each of energy 3.5 eV strike an electron of aluminium, then emission of electrons will be
|
(a) Possible |
|
(b) Not possible |
|
(c) Data is incomplete |
|
(d) Depend upon the density of the surface |
Which one of the following is the weakest kind of bonding in solids
|
(a) Ionic |
(b) Metallic |
(c) Vander Waals |
(d) Covalent |
A rectangular coil of 20 turns and area of cross- section 25 sq cm has a resistance of 100 ohm. If a magnetic field which is perpendicular to the plane of the coil changes at the rate of 1000 Tesla per second, the current in the coil is
|
(a) 1.0 ampere |
(b) 50 ampere |
(c) 0.5 ampere |
(d) 5.0 ampere |
